fahvzero

Anyone live in Abilene, TX know a reputable shop who does rear axle gears?

2014GHIGGT

If you're feeling frisky I could walk you through it. I've done hundreds and do them the right way. The biggest thing you'll need is a set of verneers and a dial indicator. If you can get those and have access to a press you're in business

fahvzero

I have been researching how to do gears on the 8.8 for about a week now and am fairly confident I can do it it's just being able to lift the car high enough and the cost of tools, I was thinking it would just be easier to pay to get it done it might cost less.

fahvzero

I looked on Google and found one place in town. I called them last year and the guy didn't sound like he knew what he was talking about. So I was hoping someone on the forum lived here and knew a good trustworthy shop in town. But if I can round up the tools that would be cool. Since I'm on the subject.

Do you know how to measure the pinion depth without the tool? I saw something online about the MHD master housing dimension of the 8.8 is 4.415. And you can measure the shim size based in the old pinion shim. Have you done that?

2014GHIGGT

If you have the old pinion, which you do, setting pinion depth can be done easily without a pinion depth tool. All you do is press off the old pinion bearing, and remove the shim. With a pair of verniers, measure the the height of the pinion gear from the face (front of the pinion gear) to the top of the bearing landing. Then measure the shim thickness that you just removed. Add the two together and that becomes your target. Measure the height of the new pinion gear from the face to the bearing landing. Subtract that number from the target number (total height from old pinion including shim) and now you know exactly how much shim to use on the new pinion before you press on the new bearing. Your pinion depth will be right on.

You only need a pinion depth tool if you are working with an entirely new setup which you are not.

Once you have your new bearing and shim pressed on to the new pinion. Reinstall the new pinion with a new crush sleeve. Set your pinion bearing pre-load to about 23 inch pounds with new pinion bearings or about 19 inch pounds using the old bearings over. You won't need to touch the pinion again during installation. Bolt on your new ring gear to your carrier and bolt the carrier assembly into the axle housing. Remember not to mix up the right and left factory carrier shims. This is important. Because one is thicker than the other.

Once you have the carrier bolted in with the factory shims in the right position, Grab a dial indicator and measure the lash. You want to target between .006 and .012. I like to get them closer to .012 but anything between the two and you'll be golden. Rarely have I ever had to re-shim the carrier. If you do just remember if you add .010 in shim to one side of the carrier, you must remove .010 from the other side of the carrier.

For example if the lash was greater than .012 you would need to shim the carrier closer to the pinion gear. So you would remove some shim from the right side of the carrier and add that same amount of shim to the left side of the carrier. It isn't rocket science. The manufacturing tolerances of these new gear sets is so good, again I have rarely had to re-shim the carrier. If you have the pinion depth right on, which you will using this method, the rest will just come together.

If you get stuck you can always reach out to me. I'll be glad to walk you through the process.

fahvzero

Thanks alot for the help I'm thinking I will do it myself. I'm thinking the hardest part is going to be getting the pinion nut preload since I won't have much room under the car to tighten it. One more question the break in period.

2014GHIGGT

Tightening the pinion nut can be a PIA. This is how I do it. I go to home depot or lowes. Grab yourself a piece of bar stock from their metal section. Get a 3/16" thick 2' wide, 36" inch long bar stock. Then grab a permanent marker. Lay the pinion flange across the bar stock so that two of the bolt holes are covered by the bar stock. Grab a permanent marker and mark the position of those two holes. Then drill out the bar stock where you marked the two holes. Once done, bolt the bar stock to the pinion flange and you can now use the bar stock to prevent the pinion flange from rotating while you crank down on the pinion nut. If you want shoot me a PM and I'll take a picture of the bar stock I use. sometimes a picture is worth a thousand words. it will make perfect sense to you once you see what I just described.

2014GHIGGT

remember the pre-load is in inch pounds. Once you begin crushing the sleeve the pre-load will come on quickly. I recommend checking pre-load every 1/8 of a turn once the crush sleeve begins getting squashed.

fahvzero

OK hahaha this should be the last question. Carrier preload. I read that after the measurements are found correct you have to add the same size shim on each side of the carrier, but didn't they do that at the factory? So it should already have the preload shims already right? I don't have to add more?

2014GHIGGT

Yes. if you are reusing the factory carrier shims, you won;t need to be concerned with pre-load. How many miles are on your car?

fahvzero

21,000 miles. Have you ever tried the method where you heat up the bearings in an oven instead of pressing them is that safe for the bearing?

2014GHIGGT

with 21,000 miles you should be OK using the old carrier bearings over.

With regards to the oven method. Yes I have had success using this method. I would put the pinion gear in the freezer overnight. But the pinion bearing in the oven for about 20 minutes at 250 degrees. The thing with this method is that if you aren't quick enough, and I mean quick, the bearing gets stuck about half way down the pinion shaft and you end up pressing it on the remainder of the way.

Either way you'll need a press to remove the old bearing so you can properly measure the pinion gear height and the factory shim. Otherwise you won't know how much shim to use for the new pinion bearing.

GrabberBlue5.0

What gears do you have now where you fell necessary for a change?

fahvzero

I have the 3.15s I have done some math on this in 3rd 4th and 5th with a 4.10 gear the auto 6r80 gears are longer than the 3.73 manual. Yes first gear is a 4.17 so it's really short but second gear is just a little shorter than the 3.73 manual. That's s 4.10 auto. I have the select shift auto and only shift manually in sport mode and in a race with a manual with a 3.73 gear and my car with a 3.73 even though I still have an overall taller gear ratio the auto doesn't have that split second pause when changing gears so it shifts quicker a 4.10 which is real close would be even quicker but traction would be the issue

GrabberBlue5.0

You are about to make a big mistake much like many before you already have. The fastest N/A autos run either a 3.15 or 3.31 gear. Depending on intake choice a 3.31 gear with a 28" tire has you finishing at the top of 3rd which is the ticket on these cars.

I've run a best of 11.2 with my stock 3.15's. Again I urge you to rethink this before you make an epensive mistake.

These cars need a converter so if you haven't done that then that should be first thing on the list outside of a good tune obviously.

fahvzero

I'm not much of a drag racer although straight line acceleration is fun. I'm more of a corner carver and these 3.15s wind up too slow. It's not that expensive since I'm doing the work about $350 parts and tools. And having a shorter rear axle gear is more fun. 3rd 4th and 5th are longer numerically than the manual and second is a little bit shorter with 4.10s. Being that it's an auto and shifts quicker the 3.73 would be the perfect gear. Check out the attachment.

fahvzero

Well the attachment came out too small sorry about that I'll send it another way.

2014GHIGGT

I could not agree more with this advice. In all of my haste explaining how to perform the gear swap I never asked this question. Anything taller than a 3.31 for an auto is a mistake.

fahvzero

I might be the oddball on the forum, I have been reading posts on many forums and it seems like everyone is into more drag racing than corner carving. I understand why the mustang has a lice rear axle which is better for that. But I lowered the car git some koni yellows and it's super fun on twisty roads which I prefer. The 3.15s while from a dig in first are still a blast but once I'm up to speed on a corner the gears wind up a little slow for my taste a shorter gear would be more fun on twisty roads, short road course races

GrabberBlue5.0

Will a steeper gear feel faster? Yes. Will it be any faster? No. It will just be shifting more. Street, track, twisty roads the same principal still applies. Steeper gears just do not flat out help these autos. Again many have though differently only to realize their mistake. It looks like you are headed down this same path. Take it from someone here with experience.

Have you even tuned the car yet?